Cytokines in pathogenesis of peri-implantitis Uloga citokina u patogenezi periimplantitisa

General term of implantation implies insertion of biomaterials of different designs into the tissues. Oral implantation is a surgical insertion of aloplastic materials (metals, alloys, ceramics, polymers, carbons as well as their combinations) into the hard and soft tissues of the upper and lower jaws . The essence of implantology lies in favorable reaction of the organism to the presence of foreign body or favorable response of the bone tissue to implant material. The organism reaction is the development of inflammation resulting in a complete recovery of tissues and acceptance of implants or its loss. Implantation is a traumatic damage of the soft and hard tissues. Regardless of how much the procedure has been carefully conducted, tissue response is controlled by mechanisms of bone healing metabolism, as well as by other biomechanisms. As with every other tissue damage, the organism reacts with inflammation with the aim to limit the damage or to replace the lost or damaged tissue with the processes of regeneration or reparation . Metabolic activities of the bone marrow and the constant process for bone remodeling are important prerequisites of the long-term implant stability. Successuful outcome of implant placement depends on: implant material, design, adequate patient selection and proper indicators, careful surgical technique used and creation of functional and esthetic prosthetic restoration. Each implant material should be: biocompatible, bioinert, biofunctional and bioadhesive . Biocompatibility means that implant material is not toxic, cancerogenic, allergenic, i.e. induces no immune reaction. In other words, histocompatibility is a “harmony” of implant material and living tissues that do not harm each other. Bioinertia primarily refers to material insolubility and stability, and resistence to corrosion, in tissue fluids. Biofunctionality includes implant design, its strenght and ability to withstand loading conditions. Bioadhesion is characterized by close intimate contact of implant surface and the surrounding tissuess. Ideal implant material which meet all the four-mentioned criteria has not yet been produced, but the common opinion is that it is sufficient that the human organism tolerates inserted material. The condition of peri-implant soft and hard tisuess is highly significant for implant longevity and function . The main role of soft tissue surrounding implants is to provide the hermetic seal and protective barrier between oral cavity and the internal peri-implant bone, thus preventing invasion of various pathogens. Bone tissue, on the other hand is responsible for implant osseointegration, stability, overtime and distribution of masticatory forces. There are many contradictory facts concerning peri-implant tissue. It is believed that hemidesmosome and basal membrane, similar to natural tooth, are the mediators for epithelial cell adhesion to the implant surface .